The associations of fat tissue and muscle mass indices with all-cause mortality in patients undergoing hemodialysis.

Takahiro Yajima,Keigo Yasuda,Kumiko Yajima,Maiko Arao,Hiroshi Takahashi,Tatsuo Shimosawa

doi:10.1371/journal.pone.0211988

Takahiro Yajima, Keigo Yasuda + Show 4 more

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https://doi.org/10.1371/journal.pone.0211988

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Journal: PloS one	Publication Date: Feb 13, 2019
Citations: 35	License type: CC BY 4.0

Affiliation: Matsunami General Hospital, Fujita Health University

Abstract

Protein-energy wasting, which involves loss of fat and muscle mass, is prevalent and is associated with mortality in hemodialysis (HD) patients. We investigated the associations of fat tissue and muscle mass indices with all-cause mortality in HD patients. The study included 162 patients undergoing HD. The fat tissue index (FTI) and skeletal muscle mass index (SMI), which represent respective tissue masses normalized to height squared, were measured by bioimpedance analysis after dialysis. Patients were divided into the following four groups according to the medians of FTI and SMI values: group 1 (G1), lower FTI and lower SMI; G2, higher FTI and lower SMI; G3, lower FTI and higher SMI; and G4, higher FTI and higher SMI. The associations of the FTI, SMI, and body mass index (BMI) with all-cause mortality were evaluated. During a median follow-up of 2.5 years, 29 patients died. The 5-year survival rates were 48.6%, 76.1%, 95.7%, and 87.4% in the G1, G2, G3, and G4 groups, respectively (P = 0.0002). The adjusted hazard ratio values were 0.34 (95% confidence interval [CI] 0.10–0.95, P = 0.040) for G2 vs. G1, 0.13 (95%CI 0.01–0.69, P = 0.013) for G3 vs. G1, and 0.25 (95%CI 0.07–0.72, P = 0.0092) for G4 vs. G1, respectively. With regard to model discrimination, on adding both FTI and SMI to a model with established risk factors, the C-index increased significantly when compared with the value for a model with BMI (0.763 vs. 0.740, P = 0.016). Higher FTI and/or higher SMI values were independently associated with reduced risks of all-cause mortality in HD patients. Moreover, the combination of the FTI and SMI may more accurately predict all-cause mortality when compared with BMI. Therefore, these body composition indicators should be evaluated simultaneously in this population.

Highlights

Protein-energy wasting (PEW), defined as the loss of body protein mass and fuel reserves, is a common complication of chronic kidney disease and is an important predictor of mortality in patients with end-stage renal disease undergoing hemodialysis (HD) [1, 2]
We have recently reported that abdominal fat levels measured by computed tomography were negatively associated with risks for all-cause mortality in HD patients [7]
The fat tissue index (FTI) and skeletal muscle mass index (SMI), which represent respective tissue masses adjusted for height squared, have been used to evaluate fat mass and muscle mass, respectively, and the SMI is used for the diagnosis of sarcopenia when muscle mass is measured by bioelectrical impedance analysis (BIA) [10,11,12]

Summary

Introduction

Protein-energy wasting (PEW), defined as the loss of body protein mass and fuel reserves, is a common complication of chronic kidney disease and is an important predictor of mortality in patients with end-stage renal disease undergoing hemodialysis (HD) [1, 2]. Fat tissue and muscle mass indices predicting all-cause mortality epidemiologic studies have reported that a high body mass index (BMI) is associated with better survival in this population, and this phenomenon is referred to as the “obesity paradox” [3, 4]. Different results have been reported with regard to the relationship between body composition and mortality [13,14,15,16], and few studies have evaluated the associations between both fat mass and muscle mass and all-cause mortality simultaneously [10,17].

Results

Conclusion